You are a forensic scientist working at a crime scene outside along a fairly busy road. It is late at night and it is beginning to rain. You must finish what you are working on before the rain ruins the evidence. Because it is dark, you are afraid you will be hit by a passing car and decide to set up flares to divert traffic around the area. The labels on the flares have been partially torn and you cannot read which ones will burn when wet, so you look at the ingredient label on each one for a clue. Which flare should you use? A. Flare 3 contains potassium (K).
B. Flare 4 contains sulfur (S).
C. Flare 2 contains zinc (Zn).
D. Flare 1 contains magnesium (Mg).

fe 55.85 g/mol and h2o 18.02 g/mol.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

rosa was looking for patterns to predict the products of chemical reactions. she recorded three similar decomposition reactions in the table.she should record 2licl + 3o2.

in the last row of the table. it is the thermal decomposition of chlorate lithium, hence, she should record these products as: lithium chloride ( 2licl ) and oxygen ( 3o2 )   2 > 2 licl + 3o2.